全文获取类型
收费全文 | 13350篇 |
免费 | 1821篇 |
国内免费 | 97篇 |
专业分类
耳鼻咽喉 | 205篇 |
儿科学 | 476篇 |
妇产科学 | 253篇 |
基础医学 | 2019篇 |
口腔科学 | 263篇 |
临床医学 | 1579篇 |
内科学 | 2725篇 |
皮肤病学 | 178篇 |
神经病学 | 1046篇 |
特种医学 | 839篇 |
外国民族医学 | 1篇 |
外科学 | 1564篇 |
综合类 | 636篇 |
一般理论 | 8篇 |
预防医学 | 1527篇 |
眼科学 | 190篇 |
药学 | 956篇 |
2篇 | |
中国医学 | 26篇 |
肿瘤学 | 775篇 |
出版年
2021年 | 137篇 |
2020年 | 126篇 |
2019年 | 197篇 |
2018年 | 269篇 |
2017年 | 183篇 |
2016年 | 164篇 |
2015年 | 219篇 |
2014年 | 283篇 |
2013年 | 412篇 |
2012年 | 589篇 |
2011年 | 596篇 |
2010年 | 374篇 |
2009年 | 349篇 |
2008年 | 524篇 |
2007年 | 553篇 |
2006年 | 512篇 |
2005年 | 504篇 |
2004年 | 489篇 |
2003年 | 465篇 |
2002年 | 441篇 |
2001年 | 424篇 |
2000年 | 486篇 |
1999年 | 399篇 |
1998年 | 316篇 |
1997年 | 274篇 |
1996年 | 272篇 |
1995年 | 251篇 |
1994年 | 251篇 |
1993年 | 212篇 |
1992年 | 313篇 |
1991年 | 337篇 |
1990年 | 292篇 |
1989年 | 347篇 |
1988年 | 283篇 |
1987年 | 305篇 |
1986年 | 282篇 |
1985年 | 282篇 |
1984年 | 246篇 |
1983年 | 199篇 |
1982年 | 180篇 |
1981年 | 132篇 |
1980年 | 102篇 |
1979年 | 179篇 |
1978年 | 132篇 |
1977年 | 133篇 |
1976年 | 125篇 |
1975年 | 83篇 |
1974年 | 102篇 |
1973年 | 98篇 |
1972年 | 80篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Intrathecal morphine for post-thoracotomy pain 总被引:1,自引:0,他引:1
We wished to investigate possible differences in the duration of postoperative analgesia and the incidence of respiratory depression after the intrathecal injection in the lumbar area of 10 micrograms/kg morphine in hypobaric and hyperbaric solution for relief of post-thoracotomy pain. Twenty-nine patients received morphine plus dextrose (hyperbaric) and 21 received morphine in preservative-free normal saline. The duration of analgesia was longer with the morphine in the normal saline group than in the hyperbaric group (P less than 0.04). One patient developed delayed respiratory depression. Our data support the use of morphine in normal saline mixtures for greater duration of analgesia after thoracic operations. 相似文献
12.
Over the last 15 years photodynamic therapy (PDT) has become a viable treatment for pre-malignant and malignant disease of the oesophagus. Its initial use was in the palliation of oesophageal malignant obstruction bringing improved swallowing hence increasing nutritional intake and improving general quality of life. As the therapeutic boundaries of PDT have stretched, current studies look at the role of PDT in the treatment of pre-malignant dysplastic Barrett's epithelium and early malignancy as a curative mucosal ablative technique. As a curative treatment in early oesophageal cancer, PDT provides an alternative treatment to oesophagectomy for those more elderly or less medically fit patients.This paper reviews the uses of photodynamic therapy in oesophageal cancer with reference to the available publications on its use in the palliation of oesophageal cancer and treatment of early cancer and high grade dysplasia in Barrett's mucosa. 相似文献
13.
This issue of Annals of Oncology sees a report of a trial bythe Italian INTACC intergroup comparing folinic acid-modulatedfluorouracil, combined with levamisole, with fluorouracil andlevamisole alone [1]. This large trial (n = 1703) adds importantlyto our knowledge of the value of folinic acid in the fluorouracil/folinicacid (FUFA) chemotherapy combination, which is now widely acceptedas the standard regimen in colorectal cancer [2]. No statisticallysignificant differences in terms of disease-free survival oroverall survival were found from modulating the action of fluorouracilwith folinic acid. However, the absence of a statistically significantdifference does not of course establish lack of benefit. Therewere fewer deaths (32% 相似文献
14.
G. Bradley Schaefer James N. Thompson John B. Bodensteiner James M. McConnell William J. Kimberling Charles T. Gay William D. Dutton David C. Hutchings Stanton B. Gray 《Annals of neurology》1996,39(3):382-385
There are conflicting reports on the relationship between cerebellar vermal lobule hypoplasia and autism. Using quantitative magnetic resonance image analysis, we measured the cerebellar vermis in 125 normal individuals with a broad age range and 102 patients with a variety of neurogenetic abnormalities. We conclude that hypoplasia of cerebellar vermal lobules VI and VII is a nonspecific finding that even occurs in several conditions without autistic behavior. This suggests that it is not a specific neuroanatomical marker for autism, nor is cerebellar dys- genesis likely to be solely responsible for clinical autistic behaviors. 相似文献
15.
Many public and private sector efforts are devoted toward increasing the training of physicians from under-represented minority groups, yet little has been documented regarding the association between physicians' racial backgrounds and the patient populations they serve. To address this question, we use 1987 National Medical Expenditure Survey to examine the impact of race/ethnicity on the matching between physician and patients. Our results show that minority patients are significantly more likely to report having a minority physician as their regular doctor. We estimate that minority patients are five times as likely as non-minorities to report that their regular physician is a member of a racial/ethnic minority. This effect is especially pronounced among Hispanics who identify a Hispanic physician as their regular provider 19 times more often than non-minorities. After controlling for other socio-economic factors, both these figures remain significant, but drop by approximately one-half. These results support the notion that minority patients tend to see minority physicians at a disproportional rate independent of other socio-economic factors. 相似文献
16.
JM Vilanova J Figueras-Aloy J Roselló G Gómez E Gelpí R Jiménez 《Acta paediatrica (Oslo, Norway : 1992)》1998,87(5):588-592
The aim of this study was to evaluate the cerebral synthesis of eicosanoids in the asphyctic newborn and to investigate the relation between the prostanoid profiles in cerebrospinal fluid (CSF) and the appearance and severity of hypoxic-ischaemic encephalopathy (HIE). Levels of 6-keto-PGF 1-α, TXB2 , PGE2 and PGF2-α in CSF were measured in 40 full term newborns during the first day of life. Thirty of these newborns had birth asphyxia and were divided into three groups: 10 without HIE, 12 with mild HIE and 8 with moderate-severe HIE. They were compared to a control group of 10 non-hypoxic newborns. Determinations of the metabolites in CSF were performed by RIA and expressed as pg/ml (mean ± SD). The CSF TXB2 (thromboxane A2 metabolite) in asphyxiated newborns was always higher than in the control group (28.12 ± 10.6), and related to the severity of HIE ( p = 0:005): without HIE (50.84 ± 16.4; p = 0:02), mild HIE (80.65 ± 12.64; p ± 0:01) and moderate-severe HIE (178.14 ± 20.5; p < 0:01). The CSF 6-keto-PGF 1-α (prostacyclin metabolite) in asphyxiated newborns was always higher than in the control group (80.55 ± 12.56), but indirectly related to the severity of HIE: without HIE (240.95 ± 28.12; p < 0:01), mild HIE (183.65 ± 30.1; p < 0:01) and moderate-severe HIE (140.55 ± 25.12; p < 0:01). In the moderate-severe HIE group, the increase in TXB2 was higher than the rise in 6-keto-PGF 1-α . 相似文献
17.
S. Gray S. Lawrence A. Arregui N. Phillips R. Bell T. Richards T. Fukushima H. W. Taeusch 《Journal of the National Medical Association》1995,87(5):353-358
To study some of the factors relating to the care of mothers and newborns in an inner-city hospital, three sources of information were reviewed: an obstetric database including information on prenatal care and perinatal mortality, a database of all admissions to the hospital neonatal intensive care unit over the past 5 years, and a detailed questionnaire concerning attitudes and behaviors of recently delivered women. While analyses from these hospital-based data are not conclusive, the results add evidence for the following propositions: 1) Optimal prenatal care is infrequently obtained by mothers delivering at inner-city hospitals. Lack of prenatal care is clearly associated with increased perinatal mortality. While the need for prenatal care is appreciated by 98% of the mothers in this sample, the most frequent reasons why prenatal care is not obtained earlier or more frequently involve knowledge about and access to prenatal care. 2) Inner-city mothers, in general, manifest attitudes and behaviors that promote the welfare of their pregnancies and newborns. These attitudes and behaviors are in stark contrast to those that are frequently attributed to inner-city women by the media. 3) Acute perinatal medical and nursing care are perceived by many postpartum women as suboptimal, particularly in terms of the lack of respect shown to patients by nurses and doctors. 4) Improved acute obstetric and neonatal care improves perinatal morbidity and mortality of infants delivered at inner-city hospitals. 相似文献
18.
19.
Charlotte Gray 《Canadian Medical Association journal》1996,155(6):751-753
Obstetricians have been leading the fight against government fee clawbacks and income thresholds in Ontario, but the anger has quickly spread to other specialties. Ontario doctors probably haven't been this angry since their walkout in 1986, and Charlotte Gray warns that job actions, in the form of refusals to take new patients or work in hospitals, lie ahead. If health care funding restrictions continue in Ontario, warns Dr. Dick Johnston, “sooner or later, there'll be a disaster.” 相似文献
20.
Jeffrey A. Gray Stephen N. Mitchell Michael H. Joseph Grigory A. Grigoryan Sharon Dawe Helen Hodges 《Drug development research》1994,31(1):3-17
Data are reviewed, largely from experiments in the authors'laboratory, that suggest three modes of action of systemic nicotine in producing three different types of effect upon behavior and cognitive function. (1) Preexposure of a stimulus without consequence makes it harder subsequently to form associations to that stimulus, a form of selective attention known as latent inhibition. Latent inhibition is blocked by nicotine, an effect that is apparently mediated by a nicotine-induced increase in dopamine release in the nucleus accumbens. (2) A single dose of nicotine proactively increases the partial reinforcement extinction effect measured several weeks later: that is, resistance to extinction is decreased by nicotine in animals that have been trained on a continuous reinforcement schedule, and increased in animals trained on a partial reinforcement schedule. This effect appears to be due to increased synthesis of tyrosine hydroxylase in the cell bodies of noradrenergic neurons in the locus coeruleus, followed by axonal transport to the hippocampus and increased synthesis and release of noradrenaline in that structure. (3) Nicotine improves vigilance in animals with cognitive deficits due to destruction of the forebrain cholinergic projection system, either as a consequence of excitotoxic lesions of the nuclei of origin of this system or after prolonged alcohol consumption; and also in human subjects with Alzheimer's disease (in which this system undergoes degeneration). This effect is most likely due to an action at denervated cholinergic synapses in the hippocampus and neocortex. © 1994 Wiley-Liss, Inc. 相似文献